prepare for future GPLv2+ relicensing

All files under GPLv2 will get GPLv2+ changes starting tomorrow.
event_notifier.c and exec-obsolete.h were only ever touched by Red Hat
employees and can be relicensed now.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/hw/tc6393xb.c b/hw/tc6393xb.c
index b75fa60..420925c 100644
--- a/hw/tc6393xb.c
+++ b/hw/tc6393xb.c
@@ -6,6 +6,9 @@
  * Most features are currently unsupported!!!
  *
  * This code is licensed under the GNU GPL v2.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
  */
 #include "hw.h"
 #include "devices.h"